In order to facilitate the operation of door locks, electrical motors are provided for post-mount on existing locks in doors. Retrofit motors for electrical actuation of a door lock are disclosed in US patent application No. 2010 0011822 and U.S. Pat. No. 4,901,545 as well as International patent application WO2012 177609, where a bezel is used for manually opening the lock but which also has a number keypad for operating it safely in an electronic way.
Door locks that are operated electronically, for example via smartphones are gaining an increasing market share of electrical locks. An example is found on the Internet page www.August.com, disclosing a cylindrical electrical lock casing with a lock mechanism inside having a coaxial receiver for a rotating lock pin from the lock inside the door. The cylindrical lock has an outer cylindrical lock handle as part of the casing which when rotated opens the door lock. The diameter of the cylindrical lock handle gives a lower limit of the distance necessary from the centre of the cylinder, which coincides with the position of the rotating lock pin, and to the edge of the door. As compared to slimmer door locks, this lower limit for the distance implies that a specifically sized cylindrical lock casing, the size being determined for easy rotation of the cylindrical lock handle, it is only useful for certain types of doors and not for those door types, where the position of the rotating lock pin is close to the edge of the door. In other words the lock is not versatile with respect to different door types. The latter is a problem in case that the cylindrical door lock casing should be post-mounted on doors with already existing locks with a fixed position of the rotating lock pin from the lock inside the door.
Some door locks that are driven electrically, typically also have a manual lock handle in order to select a manual opening, for example in case that the electrical driving mechanism is not properly working. Such hybrid locks are disclosed in International patent application WO2005/024160 by Bendz et al, assigned to Aptus Elektronik AB, and in Danish utility model DK201000185U3 by Henning Overgaard, assigned to Poly-Control ApS.
The typical construction in such lock is a motor that via gear wheels drives a rotating lock pin that in turn moves the lock bolt. At the rotating lock pin, the lock handle is provided in traditional way. Typically, the lock handle not only has to be twisted against the friction force of the lock bolt but also the gear wheels and the motor. This, in turn, requires additional force, which can be difficult for children or with persons with reduced force in their hands.
Thus, there is a desire for door locks actuation mechanisms that are easy to use for people with reduced force in the hand and which at the same time also are versatile for post-mounting on existing door lock mechanisms.